What is the drift rate?

Most features in the atmospheres of a planet drift in longitude at different speeds. If you are interested in following a given atmospheric structure and you know its longitude at a certain time and its drift rate (number of degrees advanced per unit of time) then you can search for all images that will contain that feature.

The form to do these searches requires the following data:

• Drift rate: units of degrees per day
• Reference date. You can also introduce the date with an hour and time.
• Longitude (Reference position). This is the longitude of your atmospheric feature on the reference date. A margin of +/-10 deg to +/-60 deg can be selected. Your reference and drift rate can be defined for any the systems of longitudes used in your planetary body (System I to III in Jupiter).
• Forward/Backward: You can look for images after the reference date (Forward) or before the reference date (Backward).

The search looks for the next or previous 1000 images of the planetary body looking for all the images with your feature of your interest close to the central meridian taken into account its drift-rate, initial position at the reference date and the margin of longitudes.

Acknowledgements: This feature has been made available thanks to an initial suggestion from Marc Delcroix (Societé Astronomique de France, France).

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